Which passlock system does my truck have and how to fix it? on 2000 Oldsmobile Bravada

My truck Goes through cycles.... As in I just went nine months and didn't have a single issue... Now all of a sudden it does it two or three times a day.... It Ashlight if I leave the key all the way in the ignition And set my alarm when I exit the vehicle, When I go to started again it will nine out of 10 times start.... I'm baffled and cannot find anyone to help.... I'll take any advice someone please help!!! Thanks